A retinal ganglion cell (RGC), which may be referred to as “the ganglion cell” hereinafter, is a type of neuron located near the inner surface of the retina of the eye, and receives visual information from photoreceptors (cone cells and rod cells) via two intermediate neuron types; bipolar cells and retina amacrine cells. If the ganglion cell is damaged, a person has glaucoma that leads to narrow visual field and vision loss. So, it is important to find weakly functioning ganglion cells at an early stage and stop the progress of the disease and deterioration of the ganglion cells. As one of methods of finding deterioration of the function of the ganglion cell is a perimetry, and perimeters having various kinds of structures for carrying out such a perimetry have been proposed (see the Patent-related document 1, for instance).
It has been found that there is a closer correlation between the deterioration of the function of the above-mentioned ganglion cell and thickness of retinal inner layer (GCC thickness, the thickness of Ganglion Cell Complex), and the thickness of the retinal inner layer is thin at a portion where the function of the ganglion cell is weak. Under these situations, a method for the perimetry is to find portions where retinal inner thickness is thin based on various kinds of fundus images, such as an OCT image and a GCC thickness map made from the OCT image, and to present a stimulus on the portion so as to carry out the perimetry preferentially thereon.